Binderless zeolite catalysts, production thereof and catalytic reaction therewith

ABSTRACT

The binderless zeolite of this invention is comprised more than 90% of crystalline aluminosilicate which is produced by crystalize a binder contained in extrudate obtained by molding a mixture of crystalline aluminosilicate and binder of silica-alumina. This binderless zeolite can improve it&#39;s catalytic activity without weaken the strength of the extrudate, since a so-called secondary pores also act as catalyst. Especially, when more than 50% of TSZ zeolite is contained, the catalytic ability of binderless zeolite is so excellent that it is preferably used as the catalyst for selective cracking of n-parafins or alkylation of aromatics using alkylation agents such as alcohols and olefins. Excellent binderless zeolite can be obtained by subjecting extrudate, formed by molding a mixture of about from 30 to 70% by weight of at least one member selected from crystalline aluminosilicate, silica alumina xerogel or hydrothermally treated silica alumina xerogel, and from 70 to 30% by weight of silica alumina gel containing from 2 to 10% by weight of alumina, under hydrothermal conditions.

This is a continuation, of application Ser. No. 06/674,910 filed Nov. 9,1984, abandoned.

FIELD OF THE INVENTION

This invention relates to binderless zeolites and more particularly, toTSZ crystalline aluminosilicates having controlled secondary pore formedamong crystal grains, production processes thereof and processes usingthe same as catalysts.

BACKGROUND OF THE INVENTION

Crystalline aluminosilicates are generally known as zeolites, and bothnatural and synthetic products are hydrated aluminosilicates having acrystal structure composed fundamentally of three-dimensionalframeworks; one of which is consisting of SiO₄ tetrahedra formed bycoordinating four oxygen atoms at the apexes of a tetrahedron around thecentral silicon (Si) atom and the other three-dimensional framework isAlO₄ tetrahedra formed by replacing the silicon atom in above SiO₄tetrahedra with an aluminum (Al) atom.

It is known that the SiO₄ tetrahedra and the AlO₄ tetrahedra constitutebasic units consisting of 4-, 5-, 6-, 8-, or 12-membered units formedfrom 4, 5, 6, 8, or 12 joined tetrahedra or basic units consisting ofdouble rings formed from two such 4-, 5-, 6-, 8-, or 12-membered rings,and that the framework of a crystalline aluminosilicate is determined byinterconnection of these basic units.

There are certain cavities in the above framework structure, and theirapertures are formed with 6-, 8-, 10- or 12-membered rings. Suchcavities have a uniform diameter so that the molecules smaller than acertain size are adsorbed into them while the larger ones can not getinto them. Hence, such cristalline aluminosilicates are known as"molecularsieves" according to their functions, and used as adsorbents,catalysts for chemical reactions or catalyst carriers in a wide varietyof chemical processes.

In recent years, their applications utilizing a combination of both ofthe above mentioned functions as a molecular sieve and a catalyst havebeen energetically studied in a variety of the fields of chemicalreactions. These are the so-called molecular shape-selective reactioncatalysts and, as shown in the classification made by S. M. Csicseryaccording to their functions, they are divided into the following threetypes: (1) catalysts whose active sites can be approached only byspecial reactions, (2) catalysts in which, among the reactants whichhave reacted at the active sites, only those having special shapes canleave the reaction sites, and (3) catalysts in which, althoughindividual molecules can freely enter or leave the reaction sites for abimolecular reaction, they can not react owing to their large transitionstate ("Zeolite Chemistry and Catalysis" ACS Monograph 171, ACS,Washington D.C., 1976, p. 680).

This classification is made on the basis of only catalytic reactionstaking place in the cavities of a crystalline aluminosilicate. Namely,in case of catalytic reactions taking place at active sites on or nearthe external surface of the crystal, all reactions having low-activationenergy can take place--different from the above mentioned catalyticmolecular shape selective reactions. Therefore the selectivity of thereactions is lowered.

Accordingly, in order to control the nonselective reactions taking placeon or near the external surface of the crystal, there have been proposeda method in which the active sites are buried by coating the crystalsurface with a compound and a method in which the solid acidity of theactive sites is controlled using some compounds having different solidacidity or alkalinity--such as silicone compounds, phosphorus compounds,magnesium compounds etc.

On the other hand, a method is also known in which the ratio of thenumber of active sites (the number of active sites in the crystals,having molecular shape selectivity to that of active sites on or nearthe surface of crystal, having no shape selectivety) is controlled bycontrolling the crystal size. For example, when the crystal size isincreased, the proportion of the active sites in the crystal increasesrelatively, and the shape selectivity is heightened.

According to this method, however, the access and/or contact ofreactants to and/or with active sites are limited relatively whichresults in lowered overall reaction activity. Conversely, when thecrystal size is decreased, the proportion of the active sites on or nearthe crystal surface increases relatively then the reaction activity isheightened because of a relative increase in the chance for thereactants to approach to or contact with active sites, though the shapeselectivity is lowered.

The electrical charge of the aluminum-containing tetrahedron of acrystalline sodium aluminosilicate can be balanced by holding sodiumcations within the crystal. It is a well-known theory that these cationscan be ion-exchanged by a variety of methods to form a hydrogen-type ora metal-ion exchanged type of crystalline aluminosilicate, whichfunctions as a solid acid catalyst.

In natural crystalline aluminosilicates, the cations are Group I or IImetals of the periodic table of the elements, especially sodium,potassium, calcium, magnesium and strontium. Also in syntheticcrystalline aluminosilicates, the above metal cations are used, but theuse of organic nitrogen cations, for example, quarternary alkylammoniumions such as tetraalkylammonium ions, in addition to these metalcations, has recently been proposed.

For the synthesis of a crystalline aluminosilicate having a highsilica/alumina ratio, it has been thought essential to use anitrogen-containing organic compound as mentioned above as an alkalimetal source. The use of the nitrogen-containing organic compounds,however, has disadvantages in that the material cost is high and thatthe production process is complicated because, in order to employ theobtained synthetic aluminosilicate as a catalyst, it is necessary toremove the nitrogen-containing compounds contained in the product bycalcination at high temperatures.

Moreover, in conventional production processes using the above-mentionedtetraalkylammonium compounds or amine compounds such as C₂ to C₁₀primary amines, there has been a problem of operation safety because ofthe latent toxicity of the organic compounds or various dangersaccompanying their decomposition or the like encountered in thesynthesis, drying and calcination processes.

Furthermore, although it has been proposed to use oxygen containingorganic compounds or sulfur containing compounds, these methods can notsolve the problems encountered in using the nitrogen-containing organiccompounds.

Recently, these problems were partially solved by a invention disclosedin Japan Patent Application No. 143396/1981 (filed Sept. 11, 1981), inwhich a crystalline aluminosilicate having characteristic crystalstructure characterized by an X-ray diffraction pattern had beenobtained.

It is a crystalline aluminosilicate having a chemical composition interms of a molar ratio of oxides of 0.8˜1.5 M₂ /nO.Al₂ O₃.10˜100 SiO₂.ZH₂ O, wherein M is a metal cation, n is the valence of the metal, and Zis 0 to 40, and having the powder X-ray diffraction pattern showing atleast the interplanar spacings, i.e., d-spacings, shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        Interplanar spacings: d (Å)                                                                relative intensity (I/Io)                                    ______________________________________                                        11.2 ±  0.2   S.                                                           10.1 ± 0.2    S.                                                            7.5 ± 0.15   W.                                                           6.03 ± 0.1    M.                                                           3.86 ± 0.05   V.S.                                                         3.82 ± 0.05   S.                                                           3.76 ± 0.05   S.                                                           3.72 ± 0.05   S.                                                           3.64 ± 0.05   S.                                                           ______________________________________                                    

The aluminosilicate having a crystal structure characterized by theabove X-ray diffraction pattern was designated as TSZ.

In Table 1, the relative intensities are given in terms of the symbols:V.S.=very strong, S.=strong, M=medium, W.=weak and V.W.=very weak.

From another powder X-ray diffractiometric analysis, it was concludedthat TSZ belongs crystallographically to the monoclinic system.

On the other hand, when a zeolite catalyst is applied to an industrialprocess such as a fluidized bed of gas/oil feedstock or a fluidizedoperation, for example, in catalytic cracking, the zeolite is suppliedin the form of fine particles.

It is desirable to increase the surface area of a catalytically activezeolite as much as possible in view of the fact that only the externalsurfaces of catalyst particles can be utilized almost exclusivelybecause gas-phase reactions are usually conducted at high spacevelocities, and the diffusion from the catalyst of surface is limited inliquid phase reactions of heavy oil (U.S. Pat. No. 3,966,644 shows thatthis diffusion limit is about 1/120 in.). Although it can be improved byreducing the diameters of the catalyst particles, the particles arelowered in strength and collapsed. Therefore, the improvement ofcatalyst performances by this method is limited, and a zeolite catalysthas been applied to industrial processes, after it was molded intopellets by using a suitable binder. When this method is applied,however, the space velocity of the reactants must be lowered because theutilization rate of a zeolite is lowered, which inevitably lowers theproductivity, and in addition, a drawback that the zeolite is poisonedas a result of the movement of the alkali, alkaline earth metal or thelike contained in the binder into the zeolite arises. Further, sincesuch pellet-form catalysts are prepared by a process consisting ofmolding, by compression, a zeolite together with an amorphous binder,the amorphous binder penetrated into the so-called secondary porespresent among the zeolite crystals, and therefore neither the quantitynor distribution of secondary pores could be controlled though thephysical strength is increased.

Further, the above binder has a limitation in that it must be thermallystable and capable of forming paths for passing gases or liquids as thereactants into zeolite crystals.

A honeycomb-like solid crystal prepared by coating a conventional basewith a zeolite crystal was proposed as zeolite catalyst excellent inindustrial applications (see, for example, British Patent No. 1,441,443,U.S. Pat. Nos. 3,730,910, 3,468,815, 3,244,643, 3,697,446, etc.), but innone of these, the production is easy and the catalytic activities, thephysical strengths, catalyst activity maintenance etc., had room to beimproved.

According to U.S. Pat. No. 3,119,660, previously formed metakaolin,either alone or in admixture with zeolite A, is reacted with an alkalisolution to form 100%-zeolite A, or a soluble silica source is added tothe reaction mixture to form zeolite X or zeolite Y which is used as aconstituent of pellets or the like.

Further, a catalyst composition is provided which is prepared by buryinga zeolite in a porous matrix and which can provide paths into crystalwhile minimizing a loss due to abrasion during the operation of theactive zeolite crystal (Japan Patent Application-OPI No. 133489/1979).

However, in none of above processes, the production is easy and noconsideration is made for the so-called secondary pores present amongcrystals.

The secondary pores are formed, for example, when crystal powder ismolded. Therefore, if these pores can be kept effective withoutdecreasing pellet strength (abbreviated as binderless zeolite), thereactants can easily move from one crystal to another, and in addition,the area of the crystal surface having a catalytic activity is increasedpractically, with a consequent improvement in the catalytic activity ofthe pellets.

Accordingly, it is a first object of this invention to provide acatalyst containing TSZ zeolite having effective secondary pores andhaving a special form excellent in catalytic activity.

It is a second object of this invention to provide a binderless TSZzeolite excellent as a catalyst used in selectively cracking ofn-paraffinic hydrocarbons.

It is a third object of this invention to provide a binderless TSZzeolite excellent as a catalyst for alkylation reaction of aromaticswith alkylating agents such as alcohols or olefins.

It is a fourth object of this invention to provide a process forproducing a catalyst containing a TSZ zeolite having effective secondarypores and having a special form excellent in catalytic activity.

It is a fifth object of this invention to provide a process for readilyproducing a binderless TSZ zeolite of special form.

DISCLOSURE OF THE INVENTION

These objects have been achieved by subjecting a solid obtained bymolding a mixture prepared by mixing a previously synthesizedcrystalline aluminosilicate with a silica/alumina binder to ahydrothermal treatment--to crystallize under crystallization conditions.

As the previously synthesized crystalline aluminosilicate used in thisinvention, both of a TSZ crystalline alumino-silicate and a so-calledZSM-5 can be used. In these crystalline aluminosilicate, one which isnot calcined and is still in a state as it is synthesized is included.It is also possible to use a sodium aluminosilicate which is notcompletely crystallized but partially crystallized and shows an X-raydiffraction pattern close to that of amorphous one, and also possible touse a xerogel which is prepared by subjecting a gel to only acalcination. However, when zeolites other than the TSZ crystallinealuminosilicate are used, it is particularly preferable to use theirsodium salt form.

The TSZ crystalline aluminosilicate relating to this invention ischaracterized by an X-ray diffraction pattern obtained by a standardpowder X-ray diffractiometric analysis. Namely, the crystal structure ofthe TSZ crystalline alumino-silicate differs remarkably from those ofheretofore proposed crystalline zeolites in that the diffraction line of2θ=14.7° (d=6.03 Å) is a singlet and that the two diffraction lines of2θ=23° (d=3.86 Å) and 2θ=23.3° (d=3.82 Å) are clearly separated fromeach other. The lattice spacing of this characteristic X-ray diffractionpattern do not vary markedly even when the substituted cation of thesynthesized silicate is exchanged, especially, changed into a H form, orSiO₂ /Al₂ O₃ ratio is changed.

The TSZ crystalline aluminosilicate used in this invention which isstill in a state as it is synthesized has a preferable composition, interms of a molar ratio of oxides, of

0.8˜1.5Na₂ O.Al₂ O₃.25˜80SiO₂.O˜40H₂ O, and it is possible in this caseto replace at least part of the metallic cations (which are present whenTSZ is synthesized) by ion exchange or a like treatment. This ionexchange can be carried out by using a Group II to VIII metal of theperiodic table of the elements, hydrogen ion from acids, or ammoniumions. As far as the SiO₂ /Al₂ O₃ ratio falls within the range of 25 to80, the crystal structure does not change and the hydrogen-form of TSZis also monoclinic.

The crystalline aluminosilicate which is able to use in this inventioncan be produced generally by preparing an aqueous reaction mixtureconsisting essentially of inorganic reaction materials, prepared byusing SiO₂ as a silicon source and Al₂ O₃ as an aluminum source in aratio within a certain range and adding a suitable alkali source andwater in a ratio within a definite range, then heating and holding theaqueous reaction mixture at a crystallization temperature until crystalsare formed. Such production conditions can be realized, for example, bymaintaining at an autogenous pressure and a temperature of about 120° C.to about 230° C. for about 10 hours to 10 days.

The TSZ crystalline aluminosilicate is produced from an aqueous reactionmixture consisting substantially of inorganic reaction materialscomprising a silica source, an alumina source, an alkali source, waterand a neutral salt of an alkali metal, and the composition of saidaqueous reaction mixture in terms of a molar ratio of oxides is asfollows:

    ______________________________________                                        SiO.sub.2 /Al.sub.2 O.sub.3 :                                                                      10     ˜                                                                             130                                         Na.sub.2 O/SiO.sub.2 :                                                                             0.01   ˜                                                                             0.5                                         (Na.sub.2 O + M.sub.2 /n O)/SiO.sub.2 :                                                            0.03   ˜                                                                             0.3                                         H.sub.2 O/(Na.sub.2 O + M.sub.2 /n O):                                                             150    ˜                                                                             800                                         X.sup.- /SiO.sub.2 : 0.01   ˜                                                                             20                                          ______________________________________                                    

wherein M is a Group I or II metal cation of the periodic table of theelements, and preferably selected from the group consisting of lithium,sodium, barium, calcium and strontium, and n is the valence of themetal.

The M₂ /nO and the Na₂ O are both in a free state and generally take theform of hydroxides, or extremely weak acid salts which are effective inthe synthesis of zeolites, for example, aluminates, silicates, etc.Further, the free Na₂ O can be controlled by the addition of sulfuricacid, hydrochloric acid, nitric acid or the like.

In this invention it is possible to crystallize a silica/alumina binderwhich is amorphous in its initial state by molding a mixture prepared bymixing the above produced TSZ crystalline aluminosilicate or the likewith the silica/alumina binder into pellets, and then subjecting thepellets to the same hydrothermal treatment as in the production of theTSZ crystalline aluminosilicate, whereby the binderless zeolite of thisinvention can be obtained.

Since the silica/alumina binder used in this invention crystallizes bythe hydrothermal treatment, its composition is preferably one thatallows the ready crystallization, and particularly when the binder,having the SiO₂ /Al₂ O₃ ratio nearly equal to that of the TSZcrystalline alumino-silicate, is used with the TSZ crystallinealuminosilicate, a binderless zeolite having a particularly goodcatalyst performance can be obtained.

Although the shape of the solid used in the hydrothermal treatment isnot particularly limited in this invention, it is preferably pellet,polylobal body or hollow tube on account of the easiness of molding orthe utilization efficiency in using it as a catalyst, and with respectto its size, outside diameters of about 1.5 mm are preferred from theeasiness of handling.

The hydrothermal reaction in this invention can be carried out accordingto the method disclosed in Japan Patent Application No. 143396/1981 and,when a crystalline aluminosilicate other than the TSZ crystallinealuminosilicate is used as the crystalline aluminosilicate, it ispreferable to use a mineralizer or a cation source, and it isparticularly preferable to use NaCl as such an agent.

Further, when a so-called xerogel, which is prepared by subjecting a gelsimply to a calcination, is used, it is necessary to use more severeconditions than those when a crystalline aluminosilicate is used.

When the hydrothermal treatment in this invention is carried out, thebinder crystallizes and shows the X-ray diffraction pattern of TSZcrystalline aluminosilicate, which has the characteristics obtained whenthe synthesis is carried out without using organic cations, and thedistribution of secondary pores is extremely sharp. Although the methodof measuring the radii of secondary pores which are controlled in thisinvention is not necessary established, it is possible to estimate theiraverage radius by the so-called mercury porosimetry. In this invention,the average pore radius is defined as a radius at which the accumulatedpore volume which corresponds to 1/2 of the total pore volume measuredby the mercury porosimetry, and the size of this pore radius isimportant from the viewpoint of catalytic activity because it concernsnot only with the actual surface area of the catalyst but also affectsthe diffusion velocities of the reactant molecules and those of theformed molecules.

The binderless zeolite obtained in this invention has excellentcrystallinity as a whole. For example, when a TSZ crystallinealuminosilicate is used as a starting zeolite, it is possible to obtaina zeolite structure which is so uniform that it is almost impossible todiscriminate microscopically the TSZ crystalline aluminosilicate formedby crystallization of the binder from that used as the startingmaterial.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the powder X-ray diffraction patterns of pellets before andafter the synthesis to form the binderless zeolite in Example 1.

FIG. 2 shows the powder X-ray diffraction patterns of pellets before andafter the synthesis to form the binderless zeolite in Example 2.

FIG. 3 shows the powder X-ray diffraction patterns of pellets before andafter the synthesis to form the binderless zeolite in Example 3.

FIG. 4 shows the electron-microscopic photographs of pellets (preparedin Example 1) of 5000 magnifications. FIG. A is the cross section ofpellet (after molding) before the synthesis to form the binderlesszeolite. FIG. B is the surface of pellet after the synthesis to form thebinderless zeolite. FIG. C is the cross section of pellet after thesynthesis to form binderless zeolite.

FIG. 5 shows the electron-microscopic photographs of pellets (preparedin Example 3) of 5000 magnifications. FIG. D is the cross section ofpellet (after molding) before the synthesis to form the binderlesszeolite. FIG. E is the surface of pellet after the synthesis to form thebinderless zeolite. FIG. F is the cross section of pellet after thesynthesis to form binderless zeolite.

FIG. 6 shows the graphs illustrating the secondary pore radiusdistributions of pellets before and after the synthesis to form thebinderless zeolite obtained in Example 1.

FIG. 7 shows the graphs illustrating the secondary pore radiusdistributions of pellets before and after the synthesis to form thebinderless zeolite obtained in Example 2.

FIG. 8 shows the graphs illustrating the secondary pore radiusdistributions of pellets before and after the synthesis to form thebinderless zeolite obtained in Example 3.

FIG. 9 shows the graphs illustrating the secondary pore radiusdistributions of pellets before and after the synthesis to form thebinderless zeolite obtained in Example 4.

DESCRIPTION OF THE MOST PREFERRED EMBODIMENTS

The following examples are provided to illustrate present invention, butare not to be construed as limiting present invention in any way.

EXAMPLE 1

An aluminum sulfate solution was prepared by dissolving 4 g of aluminumsulfate in 170 g of pure water and further adding 5.7 g of concentratedsulfuric acid (95% by weight) and 18 g of sodium chloride. The obtainedsolution was mixed under agitation with a mixture of 25 g of water and63 g of water glass (JIS No. 3 water glass, Na₂ O content of 9.5% byweight and SiO₂ content of 28.6% by weight) to obtain an aqueousreaction mixture having a composition, in terms of a molar ratio ofoxides, of

    3.9Na.sub.2 O.Al.sub.2 O.sub.3.50SiO.sub.2.2184H.sub.2 O.

In this case, sodium chloride as a mineralizer was used in a molar ratioof Cl⁻ to SiO₂ of 1.02. The aqueous reaction mixture was placed in a SUSautoclave, heated and maintained at 180° C. for 20 hours under anautogenous pressure. The crystallized solid product was separated byfiltration, washed with water and dried at 110° C. 50 g of the TSZzeolite powder thus obtained was blended in a kneader with 380 g of asilica alumina wet gel (water content of 86.8% by weight) while theblend was being dried to a moldable water content, and molded intopellets (outside diameter of about 1.5 mm) through an extruder.

The silica alumina wet gel herein used was prepared by adding both of anaqueous aluminum sulfate solution containing 38.6 g of aluminum sulfate,32 g of 95% sulfuric acid and 330 g of pure water and an aqueoussolution containing 476.2 g of water glass (JIS No. 3, hereinafterabbreviated simply as No. 3) and 240.4 g of pure water to 943 g of purewater and then filtering the combined solutions.

The pellets were dried at about 110° C. for 5 hours. Chemical analysison a portion of these pellets revealed that it had a composition of78.9% by weight of SiO₂, 4.48% by weight of Al₂ O₃, 4.18% by weight ofNa₂ O, and 12.4% by weight of an ignition loss (900° C.).

The pellets were further calcined at 600° C. for about 3 hours. A 50 gportion of these pellets together with 43.2 g of sodium chloride and 619g of pure water was placed in a all stainless autoclave and crystallizedat 180° C. for 40 hours.

After lowering the temperature, the pellets were withdrawn from theautoclave, washed, dried, and subjected to a powder X-raydiffractiometric analysis to obtain the diffraction pattern of TSZ. FIG.1 shows the powder X-ray diffraction patterns before and after thesynthesis.

Further, the electron-microscopic photographs also showed that thepellets consisted almost entirely of crystalline substances andtherefore the silica alumina wet gel had been converted into TSZ. FIG. 4shows the electron-microscopic photographs of the surface and crosssection before and after the synthesis.

The determination of the pore radius distribution by the mercuryporosimetry gave a characteristic pore radius distribution curve. FIG. 6shows the pore radius distribution curves before and after thesynthesis, and the total pore volume as measured by the mercuryporosimetry after the synthesis was 0.559 cc/g, and therefore it wasevident that 30% of the total pore was contained within the range of theaverage pore radius ±20%.

The crushing strength of the pellets after drying was 1.5 kg/3 mm, whichwas a strength sufficient to withstand to practical use.

EXAMPLE 2

50 g of a silica alumina xerogel and 380 g of a silica alumina wet gel(water content of 86.8% by weight) were blended together until the blendreached a moldable water content and molded into pellets (outsidediameter of about 1.5 mm) through an extruder.

The silica alumina xerogel used herein was prepared in the followingway. An aqueous sodium aluminate solution (17.8 g of sodium aluminateand 550 g of pure water) was added to an aqueous water glass solution(515 g of NO. 3 water glass and 255 g of pure water). The resultingsolution and a hydrochloric acid solution (152.9 g of 35% hydrochloricacid and 330 g of pure water) were added to an aqueous sodium chloridesolution (91 g of sodium chloride and 760 g of pure water) to form agel. After mixing, the reaction mixture was agitated for about 30minutes, filtered, washed and dried at 110° C. for 16 hours to obtainthe silica alumina xerogel.

The preparation of the silica alumina wet gel was carried out in thesame manner as in Example 1.

The pellets were dried at about 110° C. for 5 hours. Chemical analysison a portion of these pellets revealed that it has a composition of78.4% by weight of SiO₂, 3.65% by weight of Al₂ O₃, 5.51% by weight ofNa₂ O and 12.3% by weight of an ignition loss (900° C.).

The pellets were further calcined at 600° C. for 3 hours and a 50 gportion of the pellets together with 43.2 g of sodium chloride, 1 g ofsodium hydroxide and 619 g of pure water was placed in a 1 l stainlessautoclave and crystallized at 180° C. for 64 hours.

FIG. 2 shows the powder X-ray diffraction patterns, and FIG. 7 shows thepore radius distribution curves.

The pellets has a crush strength of 1.0 kg/3 mm.

The total pore volume as determined by the mercury porosimetry after thesynthesis was 0.497 cc/g, and therefore it was evident that 30% of thetotal pore volume was contained within the range of the average poreradius ±20%.

EXAMPLE 3

70 g of a hydrothermally treated silica alumina xerogel and 532 g of asilica alumina wet get (water content of 86.8% by weight) were blendedtogether until a moldable water content was reached, and molded intopellets (outside diameter of about 1.5 mm) through an extruder. Thehydrothermally treated silica alumina xerogel herein used was preparedby adding an aqueous aluminum sulfate solution (19.7 g of aluminumsulfate, 21.1 g of 95% sulfuric acid, and 210 g of pure water) and anaqueous water glass solution (303 g of No. 3 water glass and 153 g ofpure water) to an aqueous sodium chloride solution (90 g of sodiumchloride and 600 g of pure water) to form a gel, agitating the mixturefor about one hour, placing the mixture in a 1 l stainless autoclave,subjecting the mixture to a hydrothermal treatment at 160° C. for 20hours under an autogenous pressure and, after filtration and washing,drying the product at 110° C. for 20 hours. A portion of these pelletswas taken and subjected to a powder X-ray diffractiometric analysis. Itwas found to be amorphous.

The preparation of the silica alumina wet gel was carried out in thesame manner as in Example 1.

The molded pellets were dried at about 110° C. for 20 hours, andcalcined at 550° C. for 3 hours. Chemical analysis on a portion of thesepellets revealed that it had a composion of 87.1% by weight of SiO₂,4.02% by weight of Al₂ O₃, 6.09% by weight of Na₂ O, and 2.52% by weightof an ignition loss (900° C.).

A 50 g portion of the pellets, together with 43.2 g of sodium chloride,1 g of sodium hydroxide and 688 g of pure water, was placed in a 1 lstainless autoclave and crystallized at 180° C. for 40 hours.

FIG. 3 shows the results of powder X-ray diffraction patterns, FIG. 5shows the electron microscopic photographs, and FIG. 8 shows the poreradius distribution curves.

The pellets after drying had a crushing strength of 1.9 kg/3 mm.

The total pore volume as determined by the mercury porosimetry after thesynthesis was 0.401 cc/g, and therefore it was evident that 39% of thetotal pore volume was contained within the range of the average poreradius ±20%.

EXAMPLE 4

50 g of α-Al₂ O₃ powder and 335 g of a silica alumina wet gel (watercontent of 86.6% by weight) were blended together in a kneader until amoldable water content was reached, and molded into pellets (outsidediameter of about 1.5 mm) through an extruder.

The α-Al₂ O₃ was prepared from heat-treated gibbsite at 1250° C. for 20hours and showed only the diffraction pattern of α-Al₂ O₃ when analyzedby powder X-ray diffractiometry.

The silica alumina wet gel was prepared in the same way as in Example 1.

The molded pellets were dried at about 110° C. for 20 hours and calcinedat 600° C. for 3 hours. Chemical analysis on a portion of the pelletsrevealed that it has a composition of 38.5% by weight of SiO₂, 51.9% byweight of Al₂ O₃, 3.34% by weight of Na₂ O, and 5.85% by weight of anignition loss (900° C.).

A 50 g portion of these pellets was taken and placed together with 48 gof sodium chloride, 19 g of sodium hydroxide and 68 g of pure water, ina 1 l stainless autoclave and crystallized at 185° C. for 46 hours.

After lowering the temperature, the pellets were withdrawn from theautoclave and after drying, subjected to a powder X-ray diffractiometricanalysis to obtain the diffraction patterns of TSZ and α-Al₂ O₃.

The determination of the pore radius distribution by the mercuryporosimetry gave characteristic pore radius distribution curves shown inFIG. 9.

The crush strength of the pellets was 2.3 kg/3 mm.

The total pore volume as determined by the mercury porosimetry after thesynthesis was 0.604 cc/g and therefore it was evident that 41% of thetotal pore volume was contained within the range of the average poreradius ±20%.

EXAMPLES 5 TO 8

Samples which were prepared by blending and molding in the same way asin Example 3 were calcined at 550° C. for 3 hours. Then, the influencesof the addition of NaCl or NaOH were examined. The results are shown inTable 1.

                                      TABLE 1                                     __________________________________________________________________________    Example   5     6      7      8                                               __________________________________________________________________________    Extrudates (g)                                                                           10.0 10.0   10.0   10.0                                            NaCl (g)  --     9.6   --     --                                              NaOH (g)  --    --      0.37   0.64                                           H.sub.2 O (g)                                                                           137.5 137.5  137.5  137.5                                           Crystallization                                                                         180° C. ×                                                              180° C. ×                                                               180° C. ×                                                               180° C. ×                          conditions                                                                              40 hrs.                                                                             40 hrs.                                                                              40 hrs.                                                                              40 hrs.                                         Crystallinity                                                                           Amorphous                                                                           Good   mixed crystal                                                                        mixed crystal                                                          with α-SiO.sub.2                                                               with Mordenite                                  Crushing strength                                                                        2.5   2.0    1.1    0.3                                            (kg/3 mm)                                                                     __________________________________________________________________________

The powder X-ray diffraction intensities of Example 6 were same to thoseof Example 3.

EXAMPLES 9 TO 14

Samples prepared by blending and molding in the same way as in Example 1were calcined at 600° C. for 3 hours. Then, the influences of sodiumsalt or a cation source were examined. The obtained results shown inTable 2 demonstrated that these factors were important.

                                      TABLE 2                                     __________________________________________________________________________    Example 9    10   11   12   13   14                                           __________________________________________________________________________    Extrudates (g)                                                                        10.0 10.0 10.0 10.0 10.0 10.0                                         NaCl (g)                                                                              --    9.6 --    9.6 --    9.6                                         NaO.sub.2 SO.sub.4 (g)                                                                --   --   --   --    9.6 --                                           NaOH (g)                                                                              --   --    0.2  0.2  0.2 --                                           TMAOH (g)                                                                             --   --   --   --   --    1.8                                         H.sub.2 O (g)                                                                         137.5                                                                              137.5                                                                              137.5                                                                              137.5                                                                              137.5                                                                              137.5                                        Crystallization                                                                       185° C.                                                                     185° C.                                                                     185° C.                                                                     185° C.                                                                     185° C.                                                                     185° C.                               conditions                                                                            × 44 hrs.                                                                    × 44 hrs.                                                                    × 44 hrs.                                                                    × 44 hrs.                                                                    × 44 hrs.                                                                    × 44 hrs.                              Crystallinity                                                                         Bad  Good Moderate                                                                           Good Good Bad                                          __________________________________________________________________________     Note:                                                                         TMAOH refers to 30% of aqueous solution of tetramethylammonium hydroxide.

EXAMPLE 15 to 21

Samples which were prepared by carrying out blending and molding in thesame way as in Example 1 were calcined at 600° C. for 3 hours. Then, theinfluences of the addition of NaCl were examined. The results shown inTable 3 demonstrated that the addition of NaCl was extremely importantin this invention.

                                      TABLE 3                                     __________________________________________________________________________    Example 15   16   17   18   19   20   21                                      __________________________________________________________________________    Moldings (g)                                                                          10.0 10.0 10.0 10.0 10.0 10.0 10.0                                    NaCl (g)                                                                              --    1.2  4.8  2.4  4.8  9.6 --                                      NaOH (g)                                                                              --   --   --    0.2  0.2  0.2  0.2                                    H.sub.2 O (g)                                                                         137.5                                                                              137.5                                                                              137.5                                                                              137.5                                                                              137.5                                                                              137.5                                                                              137.5                                   Crystallization                                                                       185° C.                                                                     185° C.                                                                     185° C.                                                                     185° C.                                                                     185° C.                                                                     185° C.                                                                     185° C.                          conditions                                                                            × 4 hrs.                                                                     × 4 hrs.                                                                     × 4 hrs.                                                                     × 4 hrs.                                                                     × 4 hrs.                                                                     × 4 hrs.                                                                     × 4 hrs.                          Crystallinity                                                                         Bad  Moderate                                                                           Good Good Good Good Moderate                                __________________________________________________________________________

EXAMPLE 22

30 g of the sodium form TSZ catalyst obtained in Example 1 was subjectedto an ion exchange treatment at 80° C. four times (the treating time foreach being 1.5 hours) by using a 5 wt. % ammonium chloride solution inan amount of 15 ml per 1 g of TSZ. Then, the ion-exchanged product waswashed with water, dried at 100° C. and calcined in air at 550° C. for 3hours to obtain H-TSZ (hydrogen form TSZ) catalyst. This H-TSZ contained0.02% by weight of Na₂ O.

This catalyst was pulverized and classified to a size of ASTM 60/80mesh. A 0.2 g portion of the powder was placed in a glass flow reactor.

A solution prepared by mixing n hexane with 3-methylpenthane in a weightratio of 1:1 was cooled to 10° C. and passed together with nitrogen as acarrier gas so that the weight hourly space velocity (W/H/W) could be1.36. Table 4 shows the reaction rates at 300°, 350° and 400° C. after0.5 hour.

Comparative Example 1

The TSZ zeolite prepared according to the method of Example 1 wasconverted into H (hydrogen) form TSZ in the same manner as in Example22. This H-TSZ contained 0.02% by weight of Na₂ O.

The wet gel used in Example 1 of the present application was thoroughlywashed with a 1.5% ammonium carbonate solution. This wet gel was driedat 110° C. for 5 hours, and subjected to chemical analysis. It was foundthat the Na₂ O content was 0.05% by weight.

The binder thus obtained was mixed with the zeolite so that the weightratio of the former to the latter could be in the range of 70:30 aftercalcination at 600° C. for 3 hours, and molded. The extrudate wascalcined at 660° C. for 3 hours, pulverized in the same way as inExample 22, and classified to a size of ASTM 60/80 mesh. A 0.2 g portionof this powder was placed in a glass flow reactor.

The reaction was carried out in the same manner as in Example 22 of thepresent application, and the results shown in Tables 4 and 4' wereobtained.

These results demonstrated that the binderless zeolite catalyst of thisinvention was particularly excellent in respect of reaction rates andyields of aromatics.

The weight hourly space velocity (W/H/W) in this case was adjusted to0.95 (W/H/W) so as to coincide with the case of Example 22.

                  TABLE 4                                                         ______________________________________                                        Rate constant   k (hr .sup.- 1)                                               Temperature (°C.)                                                                      300        350    400                                         ______________________________________                                        Example 22                                                                    n-hexane        0.40       1.22   2.58                                        3-methylpentane 0.04       0.29   0.96                                        Comparative Example 1                                                         n-hexane        0.37       0.78   1.42                                        3-methylpentane 0.05       0.21   0.68                                        ______________________________________                                        Temperature (°C.)                                                                             300      350   400                                     ______________________________________                                        Example 22                                                                    Product         H.sub.2                                                                              0.39     1.12  1.37                                    composition     P      82.1     63.0  54.8                                    (% by weight)                                                                                 O      15.8     25.4  24.6                                                    Ar     1.7      10.5  19.3                                    Comparative Example 1                                                         Product         H.sub.2                                                                              0.40     0.66  0.57                                    composition     P      82.4     71.2  63.3                                    (% by weight)                                                                                 O      15.0     22.3  26.1                                                    Ar     2.2      5.8   10.0                                    ______________________________________                                         P: Paraffins,                                                                 O: Olefins,                                                                   Ar: Aromatics                                                            

EXAMPLE 23

The binderless catalyst (H-TSZ) obtained in Example 22 was pulverizedand classified to a size of ASTM 25/60 mesh. A 3 g portion of this wasplaced in a glass flow reactor, through which a starting materialcomprising a 1,2,4-trimethylbenzene/methanol mixture (molar ratio of1/2) as shown in Table 5 was passed at 325° C. Table 5' showsconversions of trimethylbenzene, selectivities for C₁₀ aromatic productsand isomer distributions of C₁₀ aromatic products which were measured 4hours after the start of the reaction.

Comparative Example 2

The binder and the H-TSZ which were obtained in Comparative Example 1were pulverized together and the powder was classified to a size of ASTM25/60 mesh. A 3 g portion of this was placed in a glass flow reactor,through which a starting material comprising a1,2,4-trimethylbenzene/methanol mixture (molar ratio of 1/2) as shown inTable 5 was passed at 325° C. While the weight hourly space velocity inExample 23 was 3.2 W/H/W, that in this Example was set at 2.3 W/H/W sothat both of the space velocities of the materials over the zeolitecatalyst would be equal. Table 5' shows the results together with thoseof Example 23.

These results demonstrated that the binderless zeolite catalyst of thisinvention was extremely excellent in selectivities for C₁₀ aromaticproducts.

                  TABLE 5                                                         ______________________________________                                        Reaction Conditions                                                                          Example 23                                                                              Comparative Example 2                                ______________________________________                                        Catalyst obtained in                                                                         Example 22                                                                              Comparative                                          Material:                Example 1                                            TMB/methanol (mol/mol)                                                                       1/2       1/2                                                  Temperature (°C.)                                                                     325       325                                                  Pressure       Atmospheric                                                                             Atmospheric                                          Weight hourly space                                                                          3.2       2.3                                                  velocity (W/H/W)                                                              Conversion: TMB (%)                                                                          22.4      19.3                                                 Yield of aromatic product                                                                    100.3     100.1                                                (mol % based on TMB)                                                          ______________________________________                                                                          Comparative                                 Results of reaction     Example 23                                                                              Example 2                                   ______________________________________                                        Selectivity for                                                                           C.sub.6     0         0.3                                         aromatic product                                                                          C.sub.7     0.2       1.6                                         (molar %)   C.sub.8     6.8       13.7                                                    C.sub.9     6.4       10.9                                                    C.sub.10    84.4      73.4                                                    C.sub.11 .sup.+                                                                           2.2       0.1                                         Isomer      1, 2, 4, 5-TeMB                                                                           88.6      88.6                                        distribution of                                                                           1, 2, 3, 5-TeMB                                                                           4.6       5.3                                         C.sub.11 aromatic                                                                         1, 2, 3, 4-TeMB                                                                           5.6       3.9                                         products    Others      1.2       2.2                                         ______________________________________                                         Note:                                                                         TMB refers to 1, 2, 4trimethylbenzene                                         TeMB refers to tetramethylbenzene                                        

EXAMPLE 24

The binderless catalyst (H-TSZ) obtained in Example 22 was pulverizedand classified to a size of ASTM 25/60 mesh. A 1 g portion of this H-TSZwas placed in a glass flow reactor. A toluene/ethylene/hydrogen mixture(molar ratio of 5/1/5) was passed over the catalyst at atmosphericpressure and a weight hourly space velocity of toluene of 6.5 W/H/W. Theliquid product recovered during a period from 4.5 to 5.0 hours after thestart of the reaction was analyzed gas-chromatographically to determinethe conversion of toluene, and the isomer distribution of ethyltolueneproducts. Table 6 shows the results.

Comparative Example 3

The H-TSZ obtained in Comparative Example 1 was blended with an aluminabinder (Na₂ O content of 0.005% by weight) prepared from aluminumsulfate and sodium aluminate used in amounts to provide a weight ratioof the former to the latter of 70/30 after calcination at 600° C. for 3hours, and then molded. After drying at 110° C., the extrudate wascalcined at 600° C. for 3 hours to form a binder containing catalyst.This was classified into a size of ASTM 25/60 mesh and used in thereaction similar to that in Example 24. In this case, the weight hourlyspace velocity of toluene over the zeolite was adjusted to 4.6 W/H/W soas to coincide with the case of Example 24.

The sample recovered 4.5 to 5.0 hours after the start of the reactionwas analyzed to obtain the results shown in Table 6.

                  TABLE 6                                                         ______________________________________                                                                 Comparative                                                           Example 24                                                                            Example 3                                            ______________________________________                                        Raw Material:                                                                 toluene/ethylene/hydrogen                                                                       5/1/5     5/1/5                                             (molar ratio)                                                                 Temperature (°C.)                                                                        350       350                                               Conversion of toluene                                                                           19.22     18.76                                             (% by weight)                                                                 Isomer distribution of                                                        ethyltoluene (%)                                                              P                 30.19     28.18                                             m                 61.23     63.49                                             o                 8.58      8.33                                              ______________________________________                                    

These results demonstrated that the binderless zeolite of this inventionwas excellent in conversion of toluene and selectivity forp-ethyltoluene formation as compared with the conventional catalyst.

POSSIBILITY TO INDUSTRIAL USES

As is different from powder forms the binderless zeolite catalystobtained in this invention can be extremely easily handled in thesubsequent operations such as washing, conversion into hydrogen form andion exchange of active metal species. The binderless zeolite of thisinvention thus obtained is not only excellent in activity because ofcontrolled secondary pores but also excellent in an ability to retainits activity, and exhibits an excellent performance as a catalyst forthe selective cracking of n-paraffimic hydrocarbons or the alkylation ofaromatics with alkylating agents such as alcohols or olefins.

What is claimed is:
 1. A process for producing a binderless zeolitecatalyst which is a molded body consisting essentially of TSZcrystalline aluminosilicate, by carrying out a hydrothermal treatment ofa solid prepared by molding a mixture obtained by mixing 30 to 70 weight% of at least one member selected from the group consisting of asilica/alumina xerogel, a hydrothermally treated silica/alumina xerogeland mixtures thereof with 70 to 30 weight % of a silica/alumina gelhaving an SiO₂ /Al₂ O₃ ratio essentially equal to that of TSZcrystalline aluminosilicate, wherein said hydrothermal treatment iscarried out in an aqueous solution in the presence of a neutral sodiumsalt mineralizer in a concentration ranging from 1.5 weight % to thesolubility limit until the aluminosilicate content reaches essentially100%.
 2. A process of claim 1 wherein said hydrothermal treatment iscarried out in the absence of organic cation.
 3. A process of claim 1wherein said molding is carried out to produce pellets, polylobalbodies, or hollow tubes.